Semiconductor devices use various materials which are electrically either conductive, insulative, or semiconductive. These form a semiconductor device, often referred to as a "semiconductor". This reference will be used throughout this disclosure.
In the manufacture of semiconductors, a circuit is applied to a wafer, usually in a repeat fashion across the surface of the wafer. The circuits are tested or "probed" while the wafer is in a single piece and then the wafer is cut into individual pieces called "dice" using diamond saws. Each cut die is then mounted onto a lead frame and connected to the lead frame. This assembly is then encapsulated with a plastic molding compound resulting in a single packaged unit. At that point, a series of electrical tests of the completed circuits are made.
These tests include initial circuit testing, a burn-in test, and a final circuit testing. The burn-in test is a combined procedure in which the circuits are placed under environmental stress and exercised in these environmental stress conditions. In one system, 256 circuits are connected in an arrangement of parallel connections and the circuits are exercised in heated chambers, using common inputs and a matrix arrangement of output connections. In the units for which this invention was developed, the chambers are brought up to 1250 celsius and are exercised for up to 168 hours.
In this type of testing, individual semiconductors can not be tested at their maximum speeds and other discrete testing cannot be accomplished. For this reason, after burn-in, the semiconductors are removed and placed into tubes. The tubes are then loaded into further testing machines which are used to perform further tests on the semiconductors. This further handling involves machinery that must be adapted to handle the semiconductors in the tubes in an efficient manner. Furthermore, the semiconductors in the tubes must be tracked in an accounting system in order that the results of the tests may be associated with the particular unit under test.
Therefore, the current device handlers require "tube-to-tube" transport, wherein each device must be singulated into a test site where functional testing is done. This requires different types of test handlers for different types of semiconductor packages. It is therefore, desirable to greatly enhance semiconductor test efficiency and to reduce capital expenditures by eliminating the need for device handlers dedicated to a particular package type during final testing. It is further desirable to provide a universal design for test equipment which performs testing of semiconductor devices, with portions of the burn-in carrier assemblies in configurations specific to semiconductor package types.